Add advanced test helpers docs to guides
Add advanced test helpers docs to guides

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arunagw/rails,Stellenticket/rails,rafaelfranca/omg-rails,gauravtiwari/rails,eileencodes/rails,lcreid/rails,lcreid/rails,schuetzm/rails,jeremy/rails,tjschuck/rails,yalab/rails,Envek/rails,EmmaB/rails-1,bogdanvlviv/rails,jeremy/rails,yahonda/rails,prathamesh-sonpatki/rails,palkan/rails,bogdanvlviv/rails,fabianoleittes/rails,yhirano55/rails,Erol/rails,MSP-Greg/rails,iainbeeston/rails,eileencodes/rails,notapatch/rails,Erol/rails,esparta/rails,yhirano55/rails,yawboakye/rails,shioyama/rails,jeremy/rails,prathamesh-sonpatki/rails,flanger001/rails,schuetzm/rails,Envek/rails,repinel/rails,notapatch/rails,gauravtiwari/rails,Edouard-chin/rails,yahonda/rails,starknx/rails,lcreid/rails,joonyou/rails,betesh/rails,kddeisz/rails,notapatch/rails,yawboakye/rails,Erol/rails,flanger001/rails,Vasfed/rails,georgeclaghorn/rails,yawboakye/rails,Edouard-chin/rails,notapatch/rails,arunagw/rails,Stellenticket/rails,yawboakye/rails,Edouard-chin/rails,palkan/rails,Stellenticket/rails,tgxworld/rails,joonyou/rails,georgeclaghorn/rails,utilum/rails,gauravtiwari/rails,yahonda/rails,jeremy/rails,shioyama/rails,arunagw/rails,mechanicles/rails,repinel/rails,kddeisz/rails,shioyama/rails,kmcphillips/rails,utilum/rails,repinel/rails,mechanicles/rails,Vasfed/rails,palkan/rails,tjschuck/rails,yalab/rails,yhirano55/rails,schuetzm/rails,eileencodes/rails,repinel/rails,tjschuck/rails,mechanicles/rails,kddeisz/rails,shioyama/rails,rails/rails,BlakeWilliams/rails,fabianoleittes/rails,iainbeeston/rails,EmmaB/rails-1,georgeclaghorn/rails,kmcphillips/rails,yahonda/rails,esparta/rails,yhirano55/rails,MSP-Greg/rails,iainbeeston/rails,vipulnsward/rails,bogdanvlviv/rails,joonyou/rails,Erol/rails,betesh/rails,starknx/rails,rails/rails,tjschuck/rails,eileencodes/rails,tgxworld/rails,mechanicles/rails,utilum/rails,rafaelfranca/omg-rails,fabianoleittes/rails,esparta/rails,MSP-Greg/rails,Edouard-chin/rails,yalab/rails,rafaelfranca/omg-rails,Envek/rails,MSP-Greg/rails,iainbeeston/rails,flanger001/rails,BlakeWilliams/rails,EmmaB/rails-1,vipulnsward/rails,BlakeWilliams/rails,Stellenticket/rails,yalab/rails,Vasfed/rails,prathamesh-sonpatki/rails,Envek/rails,BlakeWilliams/rails,kddeisz/rails,kmcphillips/rails,fabianoleittes/rails,arunagw/rails,tgxworld/rails,joonyou/rails,betesh/rails,utilum/rails,betesh/rails,vipulnsward/rails,lcreid/rails,Vasfed/rails,palkan/rails,schuetzm/rails,prathamesh-sonpatki/rails,esparta/rails,starknx/rails,flanger001/rails,bogdanvlviv/rails,georgeclaghorn/rails,tgxworld/rails,kmcphillips/rails,rails/rails,rails/rails,vipulnsward/rails